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Fatty Alcohols – a review of their natural synthesis and environmental distribution Stephen M Mudge School of Ocean Sciences, University of Wales – Bangor For SDA and ERASM November, 2005
Chapter 6. Environmental Concentrations .............................................................69 Global Locations..........................................................................................................73 A. Victoria Harbour, BC – Surface Sediments ............................................................73 B1. Concepcíon Bay, Chile.........................................................................................75 B2. San Vicente Bay, Chile .........................................................................................75 C. Rio de Janeiro – surface sediments in a contaminated bay .....................................79 D1. Arade Estuary........................................................................................................80 D2. Ria Formosa lagoon – surface sediments..............................................................82 D3. Ria Formosa lagoon – suspended and settled sediments ......................................85 D4. Ria Formosa lagoon – shallow core from intertidal sediments.............................87 E. Eastern North Atlantic.............................................................................................88 F. San Miguel Gap, California – long core..................................................................91 G. Rio Grande Rise (516F of leg 72 ODP), Brazil ......................................................92 H. Falkland Plateau (511 of leg 71 ODP), S. Atlantic.................................................93 I. Guatemalan Basin (Legs 66 & 67 ODP), Central America......................................94 J1. Continental slope, SW of Taiwan...........................................................................95 J2. East China Sea, N of Taiwan..................................................................................95 K. Pasture land, Southern Australia.............................................................................98 L. Prairie Zone soils, Alberta, Canada.........................................................................99 UK Studies .................................................................................................................100 1. Conwy Estuary – Core (50 cm) .............................................................................100 2. Mawddach Estuary – surface sediments. ...............................................................103 3. Menai Strait............................................................................................................106 4. Loch Riddon, Scotland – mid-length core .............................................................106 5. Lochnagar, Scotland. .............................................................................................108 6. Clyde Sea, Scotland ...............................................................................................109 7. Loe Pool, Cornwall ................................................................................................111 8. Bolton Fell Moss, Cumbria....................................................................................112 9. Blackpool Beach – see Chapter 7. .........................................................................113 10a. Loch Lochy, Scotland – a freshwater deep loch core ........................................114 10b. Loch Eil, Scotland – a mid-depth (~70m) seawater loch core...........................114 Summary ....................................................................................................................116 Chapter 7. Multivariate Statistics ..........................................................................118 Chemometric methods of use with fatty alcohols......................................................118 PCA............................................................................................................................118 PLS.............................................................................................................................127 Recommendations ....................................................................................................131 References.................................................................................................................132 Appendix Synthetic Pathways of Detergent Alcohols …………………………...141
Chapter 1. Definitions (This chapter aims to introduce the family of
compounds, how they are referred to, the likely structures that will be found and their
chemistry from an environmental point of view).
Names and structures
Fatty alcohol is a generic term for a range of aliphatic hydrocarbons containing a
hydroxyl group, usually in the terminal position. The accepted definition of fatty
alcohols states that they are naturally derived from plant or animal oils and fats and
used in pharmaceutical, detergent or plastic industries (e.g. Dorland's Illustrated
Medical Dictionary). It is possible to find the hydroxyl (–OH) group in other positions
within the aliphatic chain although these secondary or tertiary alcohols are not
discussed to any great extent in this treatise.
The generic structure of fatty alcohols or n-alkanols can be seen in Figure 1.1 and
specific examples in Figure 1.2. The value of the n component is variable and is
discussed below.
CH3 n
OH
Figure 1.1 Generic structure of a fatty alcohol – the total number of carbons needs to be greater than 8 – 10 to be a “fatty” alcohol; shorter chain compounds have an appreciable water solubility.
The range of chain lengths for these n-alcohols can be from 8 to values in excess of
32 carbons. With such a wide range of chain lengths, the chemical properties and,
consequently, environmental behaviour vary considerably. As well as these straight
chain moieties, a range of branched chain compounds are also naturally produced by
micro-organisms in the environment. The major positions for the methyl branches are
on the carbons at the opposite end of the molecule to the terminal –OH. If the methyl
branch is one in from the end of the molecule (ω-1) it is termed an iso fatty alcohol; if
it is two in from the end (ω-2) it is called an anteiso fatty alcohol. Examples of these
Figure 1.2 Example fatty alcohol structures. The majority found in nature are of the straight chain type with smaller amounts of the branched chain compounds also being present.
Most fatty alcohols are saturated in that they have no double bonds present in their
structure. However, there are a limited number of mono-unsaturated compounds that
can be found in nature. The two most common compounds are phytol (3,7,11,15 –
tetramethyl-2-hexadecen-1-ol), an isoprene (Chikaraishi et al., 2005) derived from the
side chain of chlorophyll (Figure 1.3) and a straight chain C20 alcohol with a double
bond in the ω9 position counted from the terminal carbon (eicos-11-en-1-ol, Figure
1.4, (Kattner et al., 2003).
N
N
O
O
O
NO
O
N
OH
Mg
Phytyl side chain
phytol
Figure 1.3 The chlorophyll a molecule with the phytyl side chain labelled. Cleavage of this chain at the COO- group produces free phytol in the environment.
Table 1.1 Names and key properties of fatty alcohols from C4 to C30. The boiling point values quoted are at atmospheric pressure. + @ 20°C. BML = Below Measurement Limits
The short chain compounds (up to C8) have appreciable water solubility and would
not be classified as a “fatty” alcohol as the free compounds are more likely to be in
solution than on the solid phase (abiotic or biotic). Compounds with a chain length
greater than 10 carbons are essentially insoluble in water and will partition on to the
solid phase in the environment.
Partitioning (Kow) and sediment associations
It is usual to measure the water solubility and related factors such as Bioconcentration
Factors (BCF) through the octanol – water partition coefficient (Kow) or its log10
(LogKow). There is relatively little information published for measured Kow values for
fatty alcohols although there are some data from estimated from HPLC retention
times (Burkhard et al., 1985). Difficulties arise in the measurement of these
coefficients due to the hydrophobic – hydrophilic nature of the different parts of the
molecule (Figure 1.5). The hydroxyl group gives that end of the molecule a degree of
water solubility while the alkyl carbon chain is hydrophobic. Therefore, these
compounds sit at the interface of the octanol and water in the experimental situation.
OH
OH
increasing chain length
hydrophobic chainweakly ionisablepolar headgroup
hydrophilic group
Figure 1.5 The –OH group is weakly ionisable to form –O- and H+ and as such will “dissolve” in water. However, with increasing the alkyl chain length, the effect of this is diminished and the compound has lower water solubility. This property does allow the molecule to be used as a detergent, one of the principal anthropogenic functions of fatty alcohols.
partitioning into the solid phase which subsequently settles out. Experiments using
radiolabelled alcohols with activated sewage sludge (van Compernolle et al., in press)
measure the time dependent partition coefficients for a range of alcohols typically
used in detergent formulations (Table 1.3). The mean values can be seen in Figure
1.6; the data are presented on a log axis and a linear relationship can be seen in this
figure. These values are relatively high implying that in such a system, free fatty
alcohols will be actively scavenged by the particulate phase and may be removed with
the sludge rather than be discharged with the liquid effluent.
Table 1.3 The partition coefficients (Kd) for fatty alcohols with activated sewage sludge suspended in river water. Data from van Compernolle et al. (in press). Time (h) C12 C14 C15 C16 C18
Chapter 2. Biological Synthesis (The biochemical mechanisms that lead to their formation highlighting the differences between bacteria, that can produce odd chain and branched compounds, with everything else that produces even chain compounds.) The synthesis of fatty alcohols by living organisms is intimately linked to the
production of fatty acids. In order to understand the types of fatty alcohols present in
the environment, it is necessary to appreciate the biochemical synthetic pathways that
lead to their formation in the first place.
The formation of fatty acids can progress through two major pathways; animals, fungi
and some Mycobacteria use the type I synthetic pathway. In this system, the synthesis
takes place within a large single protein unit and has a single product in the form of a
C16 unsaturated fatty acid. This system has genetic coding in one location. In contrast,
plants and most bacteria use a series of small discrete proteins to catalyse individual
steps within the synthesis; this is termed type II fatty acid synthesis (Rock and
Cronan, 1996). These proteins are genetically encoded in several different locations.
Yeasts are intermediate between these two extremes where the synthesis activities
take place in two separate polypeptides (Lehninger et al., 1993).
Animals
Type I Fatty Acid Synthesis (FAS) occurs in animals. As well as having this initial
style of fatty acid synthesis, there are a series of subsequent reactions which lead to
the elongation of the primary fatty acid (hexadecanoic acid, C16) to higher carbon
numbers and desaturation mechanisms leading to monounsaturated products.
However, animals are unable to manufacture some fatty acids and these must be
obtained from plants in the diet (e.g. ω3 essential fatty acids).
The synthesis of fatty acids in this system occurs on a single large complex comprised
of seven polypeptides. This complex acts as the focus for a series of reactions
building the fatty acids up from an acetyl – CoA starter and malonyl – CoA subunits.
The key components in the system can be seen in Figure 2.1. The complex performs
four steps each time two carbons are added to the chain: initially CO2 is removed
from the malonyl – CoA in a condensation reaction joining the two molecules
together. NADPH is used in a reduction step converting the C = O group to C – OH.
This is dehydrated (removal of H2O) making a mid-chain double bond that undergoes
a final reduction step with more NADPH leading to a saturated alky chain.
Figure 2.1 Key compounds in fatty acid synthesis. In general, plants and animals principally use acetyl – CoA as the starter while bacteria, plants and animals may sometimes use the others as well. The net effect of this series of four sub-reactions can be seen in Figure 2.2 as the
product of the first step. The process is repeated until a 16 carbon chain has been
created. The completed fatty acid is then cleaved from the FAS complex and is
available for further reactions. This process explains why the most common fatty acid
(and frequently fatty alcohol) found in environmental systems is comprised of 16
carbons. In some cases, an extra cycle occurs and a C18 fatty acid is formed instead.
Figure 2.3 Desaturation of the acyl chain. Animals can only desaturate bonds in the ∆9 position and closer to the carboxylic acid group. Plants are able to desaturate bonds closer to the ω end of the molecule.
Plants and Bacteria
Type II FAS in bacteria and plants occurs in a similar fashion to type I but the seven
different polypeptides are independent of one another. The reactions are similar to
those above but the products then undergo a wider range of elongation and
desaturation reactions. In the case of some plants (e.g. coconuts and palms), the fatty
acid is cleaved before it reaches 16 carbons and up to 90% of the oil from these plants
may have fatty acids between C8 and C14 (Lehninger et al., 1993).
Unsaturated Compounds
Unlike most animals, plants can introduce double bonds into fatty acids at locations
other than the ∆9 position; they have enzymes that act on the ∆12 and ∆15 positions of
oleic acid (18:1ω9) but only when it is part of a phospholipid or phosphatidylcholine.
This specificity may explain why very few polyunsaturated fatty alcohols are found.
Plants frequently contain fatty acids with three or more double bonds within the
molecule. For example, the principal fatty acid within linseed oil is linolenic acid or
18:3ω3, an 18 carbon straight chain molecule with three double bonds, the first of
which is in position three from the ω end of the molecule (∆15). Animals can not
generally make these polyunsaturated compounds and must obtain them from their
diet. Once in animals, however, they may be elongated to form a range of other
biochemically active compounds such as prostaglandins (Lehninger et al., 1993).
Figure 2.7 Scheme for fatty alcohol and wax production. FAS Type I produces a C16 fatty acid that undergoes repetitive C2 chain elongation. These may be converted to “free” fatty acids by cleavage of the CoA.S group. Alternatively, the two step FAR process converts the carboxylic acid group to (i) an aldehyde and (ii) an alcohol. In many organisms, the acid and alcohol are combined to produce a long chain wax. The range of fatty alcohols produced by organisms is, therefore, dependent on the
fatty acids produced by the organism and the position within the synthesis pathway
that the FAR reactions take place. The relative lack of polyunsaturated fatty alcohols
indicates that these reactions take place before plants convert the unsaturated long
chain acids to polyunsaturated acids (Figure 2.8).
Figure 2.8 Schematic process for the formation of fatty alcohols from fatty acids. Reaction (i) is chain shortening by fatty acyl – CoA dehydrogenase; reaction (ii) is chain elongation by continued malonyl – CoA addition in plants; reaction (iii) is desaturation principally in the ∆9, ∆12 and ∆15 positions, the latter two being in plants only.
Synthesis from carbohydrates (Copepods)
There have been several studies of lipids in copepods, a small zooplankton abundant
in cool and temperate waters (Sargent et al., 1976; Sargent and Falk-Petersen, 1988;
Kattner and Krause, 1989; Kattner and Graeve, 1991; Kattner et al., 2003). In general,
copepods were heaviest and rich in lipid shortly after the spring phytoplankton bloom
and it has been implied that these organisms are making the fatty acids and alcohols
directly from the carbohydrate source rather than de novo synthesis from acetyl
subunits. The fatty acid and alcohol compositions of two Calanus species showed
high levels of C16 acids and 20:5 acid, which are characteristic for diatoms (Kates and
Volcani, 1966; Ackman et al., 1968; Kattner et al., 1983). A comparison of
particulate matter in the sea with the data from Calanus finmarchicus in spring shows
that the copepod fatty acids may originate directly from the particulate material,
which consists of diatoms and a substantial amount of detritus (Kattner and Krause,
odd chain and branched compounds are also present. Parkes and Taylor (1983)
suggest that the anteiso C15 may be indicative of sulphate reducing bacteria (SRB).
0
5
10
15
20
25
3012
iso1
3
ante
iso1
3 14
iso1
5
ante
iso1
5 15 16
iso1
7
ante
iso1
7 17
iso1
8 18 19
aerobicfaculative aerobicfaculative anaerobicSRB
Figure 3.1 The percentage straight chain and iso / anteiso branched fatty acids in different types of marine bacteria. Data from Parkes and Taylor (1983).
Chlorophyll side chain (phytol)
One of the major fatty alcohols in the environment (e.g. Mudge and Norris, 1997;
Jeng and Huh, 2004) is the phytol molecule derived from the side chain of chlorophyll
(Figure 1.3). Chlorophyll, the major photosynthetic pigment of green plants is
comprised of a tetrapyrrole ring structure co-ordinating a magnesium atom. This part
of the molecule harvests the photons of incident radiation and passes it along an
electron transport system. The phytyl side chain is mainly present to impart a degree
of hydrophobicity to reduce the water solubility and immobilise the chlorophyll
within the cells. The synthesis of the phytyl side chain is from an isoprenoid system
using mevalonic-acid and does not rely on a fatty acid precursor (Chikaraishi et al.,
2005).
Analysis of environmental samples by saponification (see Chapter 5) will release the
phytol from chlorophyll into the solvent. Therefore, the phytol may be a good
indicator of the chlorophyll in the water column. This may originate in both the
Figure 3.3 Fatty alcohol profiles (proportion data) for a range of terrestrial plants from African Grassland (Ali et al., 2005). Note the differing scales on the Y-axis.
Figure 3.7 Fatty alcohol profiles from several types of marine animal. The n-alcohols are principally short chained with a maximum carbon chain length of 16.
Kattner and Krause (1989) also found a seasonal variation between samples of
Pseudocalanus elongatus; those collected in spring had a relatively high percentage of
short chain saturated alcohols (C14+C16 = 87%) but this was reduced in summer (60%)
and winter (30%). There was a corresponding increase in the percentage of C20 and
C22 mono-unsaturated compounds (6% - 26% - 69%) through the seasons as the
copepods stored the carbon as waxes. This led Hamm and Rousseau (2003) to
speculate that the occurrence of the dissolved fatty alcohols in the post-Phaeocystis
bloom indicated the mortality of a copepod population.
The cuticular surfaces of insects are also covered by a lipid layer whose primary
function is to restrict water movement across the cuticle preventing desiccation of the
insect (Buckner et al., 1996). The major components in the cuticular extracts of
insects include hydrocarbons, wax esters, aldehydes, ketones, alcohols and acids. The
quantities and composition of free cuticular lipid can vary widely among insect
groups and sometimes within the developmental stages of the same species. In a study
of two lepidopteran species, Buckner et al. (1996) found similar fatty alcohol
compounds present in each although in one C26 had the maximum occurrence while it
was C30 in the other (Figure 3.8). In both cases, the composition is similar to that of
terrestrial plants.
0
10
20
30
40
50
60
70
80
90
100
20 22 24 26 28 30 32
Perc
enta
g
H. virescensH. zea
Figure 3.8 Fatty alcohol composition in the wax esters from two lepidopteran species, the tobacco budworm, Heliothis virescens and the corn earworm, Helicoverpa zea. Data after Buckner et al. (1996).
In general, homopteran insects produce large amounts of wax (reviewed by Nelson et
al. (1999) . This wax is in the form of filaments or particles in many whitefly species.
These particles have been identified as not being composed of wax esters but of a
mixture of a long-chain aldehyde and a long-chain alcohol; for example, the
greenhouse whitefly, Trialeurodes vaporariorum has dotriacontanal (C32 aldehyde)
and dotriacontanol (C32 alcohol). In the sweetpotato whitefly, Bemisia tabaci, the
waxes are composed of the C34 equivalents tetratriacontanal and tetratriacontanol. The
external wax of whitefly nymphs may play a role in the parasitization or predation of
nymphs which are often preferred prey over adult whiteflies. In a study of the external
Fatty alcohols are widely used in the manufacture of detergents; there are several
types with (poly)ethoxylate or sulphate adjuncts imbuing the alcohol with increased
water solubility. The most frequently used class of detergents with alcohol as the non-
polar component are the alcohol ethoxylates (AE); examples of typical structures are
shown in Figure 3.11 and mixtures used in formulations are shown in Table 3.1.
O CH2
CH2
O Hn
O SO
OO Na
Figure 3.11 Typical structures of some alcohol based detergents; alcohol polyethoxylates where n = 0 – 20 and alcohol sulphate e.g. Sodium Dodecyl Sulphate (SDS).
Table 3.1 The CAS (Chemical Abstracts Service) registry number for several blends of fatty alcohols used in detergent formulations with the principal chemical species present in each.
CAS Chemical Name Composition
111-27-3 1-Hexanol 100% Linear; >95% C6 [range C6-C10]; Even 111-87-5 Octyl alcohol 100% Linear; >90% C8 [range C6-C10]; Even
112-30-1 1-Decanol 100% Linear; >90% C10 [range C8-C12]; Even Generic 5-100% Linear; C6-12 alcohols [range C6-13]; Even or Even & odd Type A. 5-95% Linear; >= 95% C11 [range C9-C13]; Even & odd Type B. >80% Linear; > 95% C9/10/11 [range C8-C12]; Even & odd Type C. >80% Linear; > 95% C7/8/9 [range C6-C10]; Even & odd
68603-15-6 C6-12 Alcohols
Type D. 100% Linear; >=90% C8/10; <10% C6 [range C6-C12]; Even
112-42-5 Undecyl alcohol >80% Linear; >95% C11 [C9-C14]; Even & odd Generic 100% Linear; >95% C12/14/16/18 [rangeC8-C20]; even Type A. 100% Linear; >50% C12/14; >10% C16/18 [range C8-C20]; even 67762-25-8 C12-18 Alcohols
Type B. 100% Linear; >10% C12/14; >60% C16/18 [range C12-C20]; even Generic 5-100% Linear; C10-16 alcohols [range C8-18]; Even or Even & odd Type A. 100% Linear; >80% C10/12/14, <10% C16 [range C8-C18]; Even Type B. 5-50% Linear; >=95% C12/13 [range C11-C14]; Even & odd Type C. 80-95% Linear; >95% C12/13 [range C11-15]; Even & odd
67762-41-8 C10-16 Alcohols
Type D. 40-50% Linear; >95% C12/13/14/15 [range C11-C16]; Even & odd Generic 40-100% Linear; C12-16 alcohols, >95% C12/13/14/15 [range C8-C18]; Even or Even & odd Type A. >40% Linear; >95% C12/13/14/15 [range C10-C17]; Even & odd Type B. 100% Linear; >80% C12/14, <20% C16 [range C8-C18]; Even
68855-56-1 C12-16 Alcohols
Type C. 100% Linear; <10% C12, >90% C14/16 [range C10-C18]; Even
Generic 100% Linear; >95% C12/14/16 [rangeC6-C18]; Even Type A. 100% Linear; >90% C12/14 (C12>C14), <10% C16 [range C6-C18]; Even 80206-82-2 C12-14 Alcohols
Type B. 100% Linear; >95% C12/14 (C12<C14) [range C8-C18]; Even Generic >40% Linear; >95% C12/13/14/15 range [range C10-C17]; Even & odd Type A. >80% Linear; >95% C12/13/14/15 range C10-C17]; Even & odd 63393-82-8 C12-15 Alcohols
Type B. 40-50% Linear; >95% C12/13/14/15 [range C11-C16]; Even & odd
112-72-1 1-Tetradecanol 100% Linear; >95% C14 [range C12-C16]; Even Generic 5-95% Linear; >95% C12/13/14/15 [range C11-16]; Even & odd Type A. 5-95% Linear; >95% C14/15 [range C12-17]; Even & odd 68333-80-2 C14-16 Alcohols
Type B. <=5% Linear; >95% C12/13/14/15 [range C11-C16]; Even & odd
36653-82-4 1-Hexadecanol 100% Linear; >=95% C16 [range C14-C18]; Even 67762-27-0 C16-18 Alcohols 100% linear (or unstated); <10% C14, >=90% C16/18
67762-30-5 C14-18 Alcohols Generic 100% Linear (or unstated); >95% C14/16/18 [rangeC10-C20]; Even Type A. 100% Linear (or unstated); >=95% C16/18 [rangeC12-C20]; Even Type B. 100% Linear (or unstated); >95% C14/16/18 [rangeC10-C20]; Even
629-96-9 1-Eicosanol >80% Linear; >=90% C20 [range C18-22]; Even 97552-91-5 C18-22 Alcohol 100% Linear; >95% C18/20/24 [range C16-C24]; Even 661-19-8 1-Docosanol 100% Linear; >95% C22; Even
68002-94-8 C16-18 and C18 Unsaturated
100% linear; >70% C16/18, <10% C14, including 40-90% C18 unsaturated [range C12-C22]; Even
Figure 3.12 The mean free fatty alcohol chain length in STP materials (activated sludge, trickling bed filters or oxidation ditches) from Europe, Canada and USA. The error bars are 1 standard deviation. The concentration range was 0.32 – 11.2 µg.L-1 in European samples; 0.29 – 14.2 µg.L-1 for Canadian samples and 0.13 – 2669 µg.L-1 for USA samples.
These data shown in Figure 3.12 include natural fatty alcohols derived from a range
of sources within the sewage treatment system as well as anthropogenically derived
detergent alcohols (Eadsforth et al., in press; Morrall et al., in press).
The detergent formulation uses a series of ethoxylates up to ~20 and some
representative data using two typical formulations can be seen in Figure 3.13a.
Influent material to a STP will contain AEs of this general formulation. This can be
compared to measurements made in STP effluent from samples in different
geographic regions (Figure 3.13b). The n = 0 sample is the free fatty alcohol and is
substantially higher than the ethoxylates as it contains alcohols derived from non-
detergent sources as well. The distinctive EO chain pattern of the commercial material
Figure 3.13a The ethoxylate chain length in a mixture of commercial detergent formulations; this is considered typical of influent material to a STP. Figure from Wind et al. (in press).
Figure 3.13b. Distribution of ethoxylate chains by region in STP effluent. Alkyl chain lengths from C12-18 were summed per ethoxylate. Data from Eadsforth et al. (in press); Morrall et al. (in press).
The production of alcohol ethoxylates is significant with close to 1 million tonnes
produced annually worldwide (Modler, 2004). The usage and production is centred in
Figure 3.15 Production of fatty alcohols with Japan from natural and synthetic sources. Data from Modler (2004).
The fate of these alcohols is principally to alcohol ethoxylate detergents (Table 3.2)
although sulphates have been more important in the past. This usage reflects the
current trend of reducing the phosphate content in detergents and also the promotion
of “green detergents” based on their perceived synthesis from natural materials rather
than man-made precursors; it has also been suggested that these green compounds
will degrade faster in the environment than anthropogenic compounds (Modler,
2004).
Table 3.2 The usage of fatty alcohols in thousand of tonnes in detergents in Japan with a forecast of the likely 2007 numbers. Data from Modler (2004).
JAPAN 1992 1995 1998 2002 2007
Alcohol Ethoxylates + AES 58 62 65 77 80
Alcohol Sulphates 42 34 21 9 6
Other Derivatives 13 16 18 21 23
Alcohols Used as such 13 12 11 10 10
Western Europe
A similar story can be seen in Western Europe (Table 3.3); most alcohols are (and
have been) used in the production of polyethoxylates. The growth in production has
principally been led by the displacement of Linear Alkyl Sulphonate (LAS)
surfactants with alcohol-based surfactants; these have better compatibility with
enzymes, higher efficacy in low or non-phosphate powders; in Sweden and Denmark,
environmental considerations have led to their usage and there is a more favourable
price vs. performance relationship compared to Linear Alkyl Benzenes (LAB).
Table 3.3 The usage of fatty alcohols in thousand of tonnes in detergents in Western Europe. There is an overall forecast growth to 2007 of 1.8%. Data from Modler (2004).
Western EUROPE 1995 1998 1999 2002 2003
Alcohol Ethoxylates 245 302 333 419 426
Alcohol Sulphates 73 85 91 68 69
Polymethacrylate Esters 27 29 30 31 32
Fatty Nitrogen Derivatives 11 16 20 23 24
Thiodipropionate Esters 5 5 5 5 5
Other derivatives, Alcohols used as such & C20+ alcohols
64 72 75 81 85
North America
The production of fatty alcohols for use in detergents is focussed in the USA and of
those used in Canada, most originate in the USA. The production by year and type of
detergent manufactured can be seen in Table 3.4. There has been a large increase in
the use of alcohol ethoxylates although in recent years, this may have peaked and
alcohol sulphates are increasing. The end use of these alcohol based detergents is
principally within the domestic arena (~80%) with industrial applications amounting
for ~20% of the total (Figure 3.16). This latter section may increase in future as
detergents based on nonyl phenol polyethoxylates, which are known to have a poorer
behaviour in the environment being replaced by alcohol based compounds (Modler,
Figure 4.1 Schematic process for the metabolic degradation of fatty alcohols in Acinetobacter spp. The oxidation component is degrative while the FAR step builds new compounds. (a) alkane monooxygenase, (b) alcohol dehydrogenase, (c) aldehyde dehydrogenase, (d) acyl–CoA synthetase, (e) acyl–CoA reductase, (f) aldehyde reductase (alcohol dehydrogenase) and (g) acyl–CoA:alcohol transferase. Redrawn from Ishige et al. (2003).
Environmental transformations of alkanes and waxes may be mediated by bacteria
(e.g. hydrocarbon degradation) and these reactions yield alcohol intermediates. It is
worth noting at this point that naturally occurring bacteria are able to degrade waxes
(Roper, 2004). The bacterial (Pseudomonas oleovorans) alkane hydroxylase system
(Ishige et al., 2003) that is responsible for the total oxidation of an n-alkane to n-
alcohol (RCH3 + NADH + H+ + O2 → RCH2OH + NAD+ + H2O) consists of three
components: alkane hydroxylase (AlkB), rubredoxin (AlkG) and rubredoxin reductase
(AlkT). AlkB is a non-heme iron integral membrane protein that catalyzes the
hydroxylation reaction. AlkG transfers electrons from the NADH-dependent
flavoprotein rubredoxin reductase to AlkB. The resultant alcohol is oxidized to 1-
alkanoate by a membrane-bound alcohol dehydrogenase (AlkJ) and cytosolic
aldehyde dehydrogenase (AlkH). 1-alkanoate is incorporated through β-oxidation via
This is the case for relatively small compounds with chain lengths between C5 and C12
(Ishige et al., 2003). Other Gram-negative n-alkane degraders belonging to
Acinetobacter grow on longer-chain n-alkanes. Although the reactions for the longer
chain alkanes C12–C18 are principally the same as those of Pseudomonas oleovorans,
the organization of the genes is different (Ishige et al., 2003). Acinetobacter sp. strain
M-1 is characterized by its ability to use much longer-chain n-alkanes (C20–C44) and
can degrade n-alkanes up to C60 when grown on a paraffin wax mixture (Ishige et al.,
2003).
15
10
5
00 10 20 30 40
Con
cent
ratio
n (u
g/g)
Time (days)
oxic
anoxicocillating
Figure 4.2 The concentration of C16 and C16:1 fatty alcohols during oxic, oscillating and anoxic incubations of sediment with the micro-alga Nannochloropsis salina (Caradec et al., 2004).
Work by Caradec et al. (2004) on the degradation of fatty acids identified the
production of free saturated and monounsaturated C16 and C18 fatty alcohols during
anoxic and alternating oxic/anoxic incubations of algal material and natural
sediments. The production of fatty alcohols coincided with a high degree of
triacylglycerol hydrolysis; this supports a precursor-product relationship between fatty
acids esterified to triacylglycerol and the alcohols produced. The greater accumulation
of C16 alcohols observed under anoxic conditions (Figure 4.2) might reflect a lower
efficiency of anaerobic bacteria for mineralising these compounds. For the oscillating
conditions, it is possible that alcohols were produced under anoxia and consumed
Figure 4.5 Location map for a 1.5 m core analysed for fatty alcohols and other lipid biomarkers. The sills in sea lochs tend to trap both terrestrial matter that runs off from the land as well as fine grained sediments that enter from the sea and then settle out.
In sediment samples from a core collected in a Scottish sea loch (essentially, a fjord;
see Figure 4.5 for the location), the concentration of the short chain fatty alcohols
generally decreased with depth (Figure 4.6a), especially in the top 20 cm, while the
long chain compounds increased with depth (Figure 4.6b). The net effect of this can
be seen in the short / long chain fatty alcohol ratio (Figure 4.6c). In the surface
sediments there are greater concentrations of short chain, marine derived compounds
often with a sub-surface maximum. This is a common feature of several sediment
cores (Hotham, 2001; Mohd. Ali, 2003) and may be due to in situ biosynthesis by
bacteria utilising the depositing organic matter.
At the deeper depths, the concentration of the longer chain compounds is greater than
the short chain ones and a ratio of less than one can be measured. This may reflect
two distinct processes; in situ degradation of the short chain compounds or a change
in organic matter source from marine at the surface (recent past) to terrestrial at depth
(past 500 years). The difficulty in separating these two different processes will be
considered in a later chapter (statistical approaches to biomarker data).
Figure 4.6 (a) Short chain and (b) long chain fatty alcohol concentrations in a core from a sea loch and (c) the ratio between the short chain fatty alcohol (C12 – C18) / long chain (C19 – C24) (Loch Riddon, Mohd. Ali, 2003).
In some locations, terrestrial inputs are small and the short chain fatty alcohols
dominate at all depths within the sediment core. An example of this can be seen in the
Ria Formosa Lagoon, Portugal (Figure 4.7 in work by Unsworth (2001)). This is the
largest lagoon in Europe and receives little terrestrial runoff for most of the year;
when it does rain in November – February, the water tends to flush out any suspended
materials from the lagoon (Mudge et al., 1998; Mudge et al., 1999). Therefore, the
settled sediment is dominated by marine markers which can be seen in the short chain
fatty alcohol (C12 – C18) / long chain (C19 – C24) ratio (Figure 4.8). The ratio is
considerably greater than the data for the sea loch environment which will be
receiving and trapping terrestrial organic matter. Therefore, the absence of long chain
fatty alcohols indicates a marine source for the organic matter and tells the
investigator significant information about sources and their deposition in the area.
This makes the fatty alcohols a useful group of biomarkers in the marine environment
although the sterols are also useful but from a different context (Mudge and Norris,
1997).
Faro Olhão
Tavira
5 km
37°N
8°W
Rio Gilão
ATLANTIC OCEAN
Cacela
Fuseta
populationcentres
-10 -9 -8 -7 -6 -534
35
36
37
38
39
Longitude
Latit
ude
lagoon
Portugal
Spain
Inlet
MarinaSewageWorks
Ancão Basin
Esteiro deMaria Nova
Western Lagoon
CORE
Figure 4.7 The Ria Formosa Lagoon in Portugal. Although there are rivers and other site of terrestrial run off, the region is dominated by marine derived fatty alcohols.
Figure 4.9 Image from Wakeham et al. (1997) showing the rate at which different organic matter classes degrade with depth through the water column and then into surface sediments. The degradation pathway for fatty alcohols follows the general scheme advanced in
Figure 2.8; alkanes and alcohols are converted to fatty acids which enter the β-
oxidation pathway (Soltani et al., 2004). The fate of the acetyl – CoA sub-units
cleaved off during this process is usually to end up as carbon dioxide.
The short term diagenesis of fatty acids in marine sediments, the ultimate fate of most
organic carbon, indicated the following reactivity relationships (Haddad et al., 1992):
unsaturated fatty acids > branched fatty acids > saturated fatty acids. They also
detected differences within the saturated fatty acid fraction such that medium chain
length compounds (C14-C19) were degraded at rates 6-7 times faster than long chain
length compounds (C20-C34). Results of kinetic modelling indicated that no simple
relationship exists between remineralization rates and molecular weight (or carbon
chain length) and they suggest that the preferential preservation of terrestrially
derived long chain length fatty acids results from their inclusion into microbially
inaccessible matrices (Haddad et al., 1992).
Degradation Rate Constants
Haddad et al. (1992) calculated apparent degradation rate constants for n-alkanols and
phytol by assuming that they are degraded by first order kinetics and at steady state
and used the following equation:
ln C = ln C0 - k (z/s)
where C = the alcohol concentration at depth
C0 = the alcohol concentration at z = 0
k = the apparent rate constant (y-1)
z = core depth (cm)
s = sedimentation rate (cm.y-1)
The apparent rate constant can be estimated from the linear regression of loge alcohol
concentrations versus z/s. Their results from the continental slope off Taiwan (354 m
water depth and 0.33 cm.y-1 sedimentation rate) are summarised in Table 4.1.
Table 4.1 Degradation rate constants (y-1) for fatty alcohols in marine sediments (after Jeng et al. (1997). Extractable alcohols are those that can be removed from the sediment without a saponification step while the bound ones need a saponification step.
Extractable Bound
Phytol 0.015 0.011
n-alkanols 0.010 0.007
These values are similar to other published rates from Sun and Wakeham (1994) who
measured values between 0.024 and 0.070 y-1 in three locations. However, re-analysis
of data from Loch Riddon (Mohd. Ali, 2003) produces a slower degradation rate.
Plotting of the loge concentrations of the C14 and C16 fatty alcohols against the k/s
(from the equation above) can be seen in Figure 4.10. The sedimentation rate, s, was
calculated from the position in the sediment core of the increased PAH concentrations
derived from the increased burning of coal and coke from 1750 onwards. In this core,
that was 52.5 cm depth and so a sedimentation rate of 0.21 cm.y-1 was used.
0 100 200 300 400 500 600 700 800k/s
3
4
5
6
7
8Lo
ge [a
lcoh
ol]
C16
C14
Figure 4.10 Loge of the C14 and C16 fatty alcohol concentrations from a Scottish sea loch. A sedimentation rate of 0.21 cm.y-1 was calculated from the PAH profile based on the beginning of the industrial revolution circa 1750. The calculated slope for the C14 was 0.002 y-1, less than previously reported values for
bound fatty alcohols shown in Table 4.1 (Jeng et al., 1997). This may be due to
several reasons; incorrect sedimentation rates although other analyses have confirmed
the rate, better preservation in this particular site due to low bacterial activity or
altered input fluxes through time. The latter appears to be most likely as other
biomarker signatures change with time due to increased anthropogenic organic matter
deposition after the initial industrialisation period. The degradation rate of the C16 was
almost an order of magnitude less than the C14. This may be due to its increased chain
length (Jeng et al., 1997) or in situ production by biota. Shorter chain alcohols were
only present in the top few centimetres of the sediment core (e.g. C12 to 12.5 cm) and
have, therefore, degraded much quicker than the rate reported here.
chosen for extracting these compounds will, therefore, determine what components
are quantified.
The analysis of fatty alcohols in environmental samples falls into two camps; those
who extract directly into a non-polar organic solvent and those who saponify the
sediment directly. The scheme for these two methods can be seen in Figure 5.2. The
principal division is in the use of KOH for saponification directly on the sediment or
only after lipid extraction with DCM / MeOH. The different routes will yield different
values and profiles as the fatty alcohols may be associated with different matrices in
the sediment and these will change with source and age.
Sediment
DCM / MeOH KOH / MeOH
KOH saponification
wax esters alcohols free alcohols total alcohols
Extractable Bound
Figure 5.2 Typical extraction protocols for fatty alcohols. The major division is whether the sediment sample is treated directly with KOH to remove all bound compounds or is it only used after solvent extraction.
The “extractable” component is removed by dissolving it into either a DCM or
chloroform mix with 1:1 methanol (MeOH) after the methods of Folch et al. (1957).
These extractable lipids may then be saponified to break any ester linkages leaving
the free lipid in solution, sometimes as its sodium or potassium salt. In the case of
waxes, a fatty acid and a fatty alcohol are produced (Figure 5.3). These may then be
extracted separately from each other. Typically, the neutral lipids will include the
sterols and fatty alcohols and these may be extracted directly into a non-polar solvent
such as hexane (Chikaraishi and Naraoka, 2005). The fatty acids may also be
Figure 5.4 GC trace for an alkaline saponification of surface sediment (Menai Strait, North Wales) with key ions for a range of fatty alcohols. The inset shows the branched chain compounds for the odd carbon numbered species.
Table 5.2 A list of the key fragments (M+ - CH3) for fatty alcohol identification by GC-MS analysis. The iso and anteiso branched components are also included with the parent Cn m/z.
Carbon Number m/z Carbon Number m/z
10 215 20 369
11 229 21 383
12 243 22 397
13 257 23 411
14 271 24 425
15 285 25 439
16 299 26 453
17 313 27 467
18 327 28 481
19 341 29 495
20 355 30 509
Comment on inter-laboratory comparisons
No reports of inter-laboratory comparisons have been found. It is possible that since
these compounds are not routinely reported, that one has not yet been carried out.
Considering the different extraction routes possible (non-polar solvent then
saponification vs direct saponification into a polar solvent), effort may need to be
directed in this direction. A further aspect is the magnitude of the free alcohols
derived from anthropogenic sources compared to naturally derived wax alcohols.
What don’t we know?
1. Context – relative proportion of alcohols coming from natural & detergent
sources in (a) STP effluents and (b) the environment generally.
Figure 6.4 Distribution of fatty alcohols in surface sediment samples from Victoria Harbour, BC, Canada. Representative samples show the change from short chain moieties near the seaward end to longer chains in the upper reaches (Mudge and Lintern, 1999).
Figure 6.5 The ratio of C24 to C16 in surface sediment samples from Victoria Harbour. The data are organised by increasing distance from the sea (from left to right). Sample locations may be seen in Figure 6.3.
B1. Concepcíon Bay, Chile
B2. San Vicente Bay, Chile
In a study of two anthropogenically contaminated bays in Chile (Figure 6.6), sub-tidal
surface sediments were collected and extracted by alkaline saponification (Mudge and
Seguel, 1997). Fatty alcohol data were collected together with alkanes, fatty acids and
sterols. Within the alcohol data, sediment concentrations were similar to those found
elsewhere although the profile was not quite as expected (Figure 6.7).
Figure 6.10 Spatial distribution of the C22 / C16 ratio in Guanabara Bay, Brazil shown as a classed posting. Each sampling site is also labelled with the C16 concentration in ng.g-1.
The highest values of the ratio indicating terrestrial organic matter are located in the
north east of the bay adjacent to the mangrove swamps. The lowest values are toward
the outer reaches most influenced by the sea and in the north west corner near the
outfalls from the city and the large oil refinery belonging to PetroBras. The reason for
these sites being high in C16 is not immediately obvious except that it also has the
highest sterol sewage indicators as well. A comparison of the fatty alcohol profiles at
two of the sites (Figure 6.11) shows how similar they are despite site 10 having the
greatest 5β-coprostanol / cholesterol ratio, an indicator of human sewage and site 15
having a value almost seven times less. It is possible that a component of these
alcohols may have been derived from an anthropogenic source rather than a natural
one.
0
100
200
300
400
500
c12
c13
c14
iso-
c15
ante
iso-
c15
c15
c16
iso-
c17
ante
iso-
c17
c17
c18
iso-
c19
ante
iso-
c19
c19
c20
ante
iso-
c21
c21
c22
iso-
c23
ante
iso-
c23
c23
c24
c25
c26
c27
c28
Con
cent
ratio
n (n
g/g)
Site 10Site 15
Figure 6.11 The concentration profile for fatty alcohols at site 10 near the oil refinery and sewage discharge compared to site 15 near the mouth of the bay.
D1. Arade Estuary
The Arade Estuary in Southern Portugal comprises the River Arade and the tributaries
Odelouca and Boina (Figure 6.12). In the early 1990’s, there was a marked decline in
the environmental quality of the waters due to effluent from agriculture, aquaculture,
% Branched 0 to 5 5 to 7.5 7.5 to 10 10 to 15 15 to 30
Figure 6.14 (a) the concentration of the short chain fatty alcohols, (b) the long / short ratio and (c) the percentage branched chains across the Ria Formosa, Portugal.
One of the measures of bacterial activity in any system is the percentage of all fatty
alcohols in a branched configuration. In these samples, this measure can be seen in
Figure 6.14c. The highest values were associated with sites that are known to be areas
of fine grain sediment accumulation and the sediments may be anaerobic at depth. As
with other studies, the fatty alcohols in this form do not appear to be very good
indicators of sewage inputs unlike the sterols (Mudge et al., 1999) however, when
examined used multivariate techniques (Chapter 7), greater discrimination between
sites can be seen.
D3. Ria Formosa lagoon – suspended and settled sediments
A further study was undertaken to determine the sources and transport paths of
sewage derived materials in this lagoon. The data are report in Mudge and Duce
(2005). Key factors in this study were the collection and analysis of suspended
particulate matter and its relationship with settled sediments and potential origins of
the organic matter. The concentrations of fatty alcohols were significantly greater in
the potential source materials (e.g. sewage disposal sites) than either the suspended
particulate matter or the settled sediments (Figure 6.15). This decrease is not
surprising given the labile nature of these compounds.
M1M2
M3I1
I2I3
R1R2
R3S1
S2S3
N1N2
N30
5000
10000
15000
12
34
56
78
910
1112
1314
1516
1718
1920
2122
2324
2526
2728
2930
0
2000
4000
6000
8000
10000
12000
12
34
12
34
12
34
12
34
12
34
12
34
0
100
200
300
400
500
600
Sources Suspended Sinks
µg.g -1
AB BR FH IS MF OH
Figure 6.15 Total fatty alcohol concentrations in potential source materials, suspended sediments and settled sediments (sinks) in the Ria Formosa Lagoon, Portugal. (Data from Mudge and Duce (2005)).
Figure 6.18 The concentration (µg.g-1) of (a) short chain and (b) long chain fatty alcohols in a short core (60 cm) in the productive Ria Formosa lagoon, Portugal. (Data after Unsworth (2001).
E. Eastern North Atlantic
In a Ph.D. study at Bristol University, Madureira studied the lipids present within five
cores from the eastern North Atlantic (see Figure 6.1 for approximate locations or
Madureira’s thesis, (Madureira, 1994)). The results include a suite of fatty alcohols
from C16 to C28 obtained from the sediment cores after alkaline saponification. The
raw concentration data is presented in the Appendix and in Figures 6.19 and 6.20. The
distribution of the alcohols at each of the sites is biased toward the long chain
moieties with maximal concentrations in the C22 to C26 length range although the long
/ short chain ratio does indicate enrichment in the short chain marine compounds near
the surface.
If the loge of the C16 and C26 compounds for an example core are taken, a plot against
the accumulation rate of the sediment can give an indication of the degradation rate
(Figure 6.21). In this case, the rate of loss of the C16 is greater than the C26 as might be
expected from the chain length information. Here, the sedimentation rate has been
assumed (3mm.y-1) but since it is only used to compare the relative rates, the exact
Figure 6.19 The total fatty alcohol concentration (µg.g-1) and long (C22 – C28) / short (C16 – C20) ratio in three eastern North Atlantic cores. (a) 61N, (b) 59N and (c) 48N. Data after Madureira (1994).
Figure 6.20 The total fatty alcohol concentration (µg.g-1) and long (C22 – C28) / short (C16 – C20) ratio (where possible) in three eastern North Atlantic cores. (a) Bound lipids in 48N, (b) 32N and (c) 18N. Data after Madureira (1994).
Figure 6.21 The relative degradation rates shown by a plot of the loge of the C16 and C26 fatty alcohols vs. a sediment accumulation rate (assumed to be 3mm.y-1). Data for site 32N from Madureira (1994).
F. San Miguel Gap, California – long core
McEvoy (1983) conducted a study on lipids from a long core collected off the
Californian coast. In his study, McEvoy first extracted lipids into a DCM : methanol
solvent (2:1) and then saponified the lipids collected. Therefore, any wax bound fatty
alcohols that were extractable in the DCM : methanol will be quantified in this
method. Only bound, unextractable with DCM : methanol compounds will not be
included.
The results are shown in Figure 6.22. Concentrations near the surface were almost
1000 ng.g-1 but decreased with depth. By 500m, no fatty alcohols were detectable
although fatty acids could be recovered all the way down to 1000m below the surface.
Figure 6.28 The C24 / C16 ratio in settled sediments from the East China Sea. Notice the change of scale compared to Figure 6.27 (after Jeng and Huh (2004).
The authors of the work (Jeng and Huh, 2004) suggest that the region is dominated by
marine production although the settled sediment fatty alcohol profiles do not reflect
this. In the two extreme cases of the ratio shown in Figure 6.28, the concentration
profile indicates a substantial terrestrial component (Figure 6.29). If these data are
compared to the oceanic core samples of Howell (1984), considerable differences can
be seen. The Chang Jiang (Yangtze River) is the largest river in Asia and the third
longest in the world. It might be expected that considerable amounts of terrestrially
derived organic matter would be entering the East China Sea by this route, depositing
on the continental shelf off the mouth. This may provide the long chain fatty alcohols
Figure 6.29 The fatty alcohol profile for surface sediments from the East China Sea. Data after Jeng and Huh (2004). Site numbers refer to locations shown in Figure 6.27.
K. Pasture land, Southern Australia
In a study of the faecal material of grazing animals in Australia, Nash et al. (2005)
quantified a few fatty alcohols in surface water runoff from pastureland. Somewhat
surprisingly, the authors only report alcohols in the C26 – C32 range although this may
be due to concentrating their efforts on the sterols which elute on a typical GC run in
the same region. Therefore, the absence of C16 – C25 in these data does not mean they
were not present, just not quantified.
The data are presented in log (x + 1) concentration form and have been converted
back to true concentrations (Figure 6.30) for a typical sample pair. These data indicate
a predominance of the C26 fatty alcohol with smaller amounts of the other even chain
length compounds; no odd chain length compounds were reported.
Figure 6.30 Concentration of long chain fatty alcohols in runoff from pastureland in Australia (after Nash et al., 2005). Units are µg.g-1 for the particulate fraction and µg.L-1 for the filtrate.
L. Prairie Zone soils, Alberta, Canada
Soils can act as the short term repository for many biologically derived compounds.
Due to the relative stability of waxes, these may be preserved for several years. In
most cases, these are derived from terrestrial plants and so the profile is similar to that
of local plant species (Figure 6.31 after Otto et al., 2005).
Figure 6.35 The C24 / C14 ratio as a measure of either (a) change in source from marine to terrestrial with increasing depth or (b) selective degradation of the short chain alcohol.
2. Mawddach Estuary – surface sediments.
A further part of Masni Mohd. Ali’s Ph.D. project (Mohd. Ali, 2003) investigated the
surface sediment distribution of a range of lipid biomarkers including fatty alcohols,
fatty acids and sterols in the Mawddach Estuary. This is a relatively clean, sandy
location with no industrialisation although there are several domestic sewer outflows
into the system. Surface scrapes of sediments were taken at the locations indicated in
the map in Figure 6.36. Samples were collected above the tidal limit to ensure a
Figure 6.37 Profiles of fatty alcohols in samples from the Mawddach Estuary. Samples shown are from the marine environment (site 1), mid-estuary (site 12) and above the tidal limit (site 25).
Figure 6.38 Mean chain length on the n-alkanols through the Mawddach Estuary from the marine environment (site 1) to above the tidal limit (e.g. site 25).
The differences in the profile enable signatures to be developed for the different
potential sources of organic matter in the system. This will be considered in more
Figure 7.1 Two dimensional loadings plot for fatty alcohols from Blackpool Beach. Four potential source aggregations can be seen; terrestrial dominated by the long chain odd and even carbon compounds, a weak marine vector generally positive of PC1 opposite terrestrial, and two bacterial vectors, 1 and 2, characterised by either odd carbon compounds or branched compounds.
The major axis (PC1 explaining 19.2% of the variance in the data) appears to be a
marine – terrestrial axis. However, the aggregation of the potential marine animal
fatty alcohols is rather weak and is shown with a dashed arrow. PC2 (12.3%) divides
two groups of compounds that are usually classified as bacterial in origin. The short
chain odd carbon compounds load negatively on PC2 and positively on PC1 (showing
a marine bacterial source?) while all the branched compounds are to be found in the
opposite quadrant (terrestrial source?).
These putative source vectors can now be laid on the sample location aggregations,
the scores plot (Figure 7.2). The potential sources to this region (colour coded in the
figure), show that the influent material to the STP (Cmarin1 – 3), Cows and Sheep3
fall along the terrestrial vector determined from the loadings plot. In the lower right
quadrant, the samples are principally effluent from the STP (Cmaref1 – 3), river
samples (RIB1 – 3) and surface water drains. The loadings plot shows these samples
to be enriched in the short chain odd carbon fatty alcohols. In comparison, the data in
the upper left quadrant designated bacteria 2 due to the presence of iso and anteiso
branched fatty alcohols, are many of the environmental samples and none of the
potential sources. The general location of Blackpool can be seen in Figure 7.3.
-5
-4
-3
-2
-1
0
1
2
3
4
-6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6
t[2]
t[1]
CP HW1
CP HW2CP HW3
CP HW4
CP HW6
CP HW7
CP HW8
CP HW9
CP HW10CP HW11
CP HW12
CP Int1
CP Int2CP Int3
CP Int4
CP Int5
CP Int6
CP Int7CP Int8
CP Int9CP Int12
CP Int13
CP LW1
CP LW3CP LW4
CP LW5
CP LW6
CP LW7CP LW8CP LW9
CP LW10
CP LW11
CP LW12CP LW13
SP HW1
SP HW2
SP HW3
SP HW4
SP HW5
SP HW6
SP HW7SP HW8
SP HW9
SP HW10SP HW11
SP HW12
SP Int1
SP Int2
SP Int3
SP Int4
SP Int5
SP Int6
SP Int7SP Int8
SP Int9
SP Int10
SP Int11SP Int12
SP Int13
SP LW1
SP LW2
SP LW4SP LW5
SP LW6
SP LW7
SP LW8SP LW9
SP LW11
SP LW12
SP LW13
NP HW1
NP HW3
NP HW5
NP HW6NP HW7NP HW8
NP HW9
NP HW10NP HW12
NP Int1
NP Int3
NP Int4
NP Int5 NP Int6NP Int7
NP Int8
NP Int9 NP Int10
NP Int11
NP Int12
NP LW1
NP LW2
NP LW3
NP LW4NP LW5
NP LW6
NP LW8NP LW9
NP LW10
NP LW11
NP LW12
SG Int1
SG Int2SG Int3
SG Int4
SG Int5
SG Int6
SG Int7
SG Int8
SG Int9SG Int10
SG Int11
SG Int12
GS Int1GS Int3
GS Int5
GS Int6
GS Int7GS Int8
GS Int9
GS Int10
GS Int12
MANSQ1MANSQ2
MANSQ3
1O1
1O3
2O2
3O13O2
3O3
CO1
CO2CO3
RIB1
RIB2
RIB3Cmarin1 Cmarin2
Cmarin3
Cmaref1
Cmaref2 Cmaref3
GUL1GUL2
GUL3
COW1
COW2
COW3
SHEEP1
SHEEP2
SHEEP3
DONKEY1
DONKEY2
DONKEY3
marine
terrestrial bacteria 1
bacteria 2
Figure 7.2 The scores plot for the data from Blackpool Beach with the putative sources from the loadings plot overlaid. The coloured sample names indicate the triplicate analyses of potential source material to the area.
samplingarea
Figure 7.3 Location map for the samples collected on Blackpool Beach
Figure 7.4 Loadings plot for fatty alcohols from a 1.5 m core collected from Loch Riddon, Scotland.
-5
-4
-3
-2
-1
0
1
2
3
4
5
-8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9
t[2]
t[1]
0-55-8
8-11
11-14
14-1717-20
20-23
23-26
26-29
29-32
32-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-7575-80
80-8585-90
90-95
95-100
100-105
105-110110-115
115-120120-125
125-130130-135
135-140140-145
145-150
marine
terrestrial
bacteria 1
bacteria 2
Figure 7.5 The scores plot for samples down a core. The labels refer to the sampling depth (in cm). The top of the core is to the right and the bottom to the left.
It is possible to explain the trends in the data as changes in source – samples near the
surface are dominated by marine inputs which have replaced older deposits of
principally terrestrial origin. However, it is also possible to interpret the data in terms
of differential degradation rates; the waxy long chain compounds are more stable and
less readily degraded in the marine environment compared to short chain (marine
derived) compounds. These data alone do not enable a definite answer to be obtained.
However, other biomarkers are more resistant to degradation and may be used to
provide secondary evidence. A key terrestrial compound that is relatively stable is β-
sitosterol (24-ethyl cholesterol) formed in the secondary thickening of higher plants
(Mudge and Norris, 1997). A good marker is the ratio of this compound to cholesterol
which is commonly though of as being a marine marker (Mudge and Norris, 1997). A
cross plot using the sterol ratio against the fatty alcohol ratio can be seen in Figure
7.6; different regions can be seen corresponding to different depths in the core. Three
regions can be identified on the plot: A – surface samples where the rates of change of
the two markers are essentially the same; B – a region where the sterol marker
changes while the fatty alcohol one does not (this coincides with the change from
bacterial group 1 to 2 on the PCA scores plot); C – a region where the markers agree
but the rate of change is less in the alcohol marker than might be expected from the
sterol data.
0-55-88-11
11-1414-17
17-20
20-2323-26
26-29
29-32
32-35
35-4040-45
45-50
50-5555-60 60-6565-70
70-7575-80
80-8585-90
90-95 95-100100-105
105-110
110-115
115-120120-125 125-130
130-135
135-140
140-145
145-150
0 1 2 3 4 5 6 7 8sito / chol
0
1
2
3
4
long
/ sh
ort F
As
A
C
B
Figure 7.6 The relatively resistant sterol marker for terrestrial plant matter (sito / chol) plotted against the straight chain fatty alcohol marker (Σ(C19 – C24) / Σ(C12 – C18)). See text for explanation of the region codes.
Figure 7.7 The contributions plot for the STP effluent relative to the average loadings. This sample was enriched in odd carbon number, straight chain fatty alcohols, especially the C17.
A number of methods are available to improved discrimination in PCA including the
use of proportion data (removes the concentration effect), log transformation (to
improve normality) and addition of small values (to remove zeros by adding 50% of
the limit of detection – useful if doing log transforms). An example of such
improvements can be seen in Figure 7.8. The loadings for fatty alcohols from the Ria
Formosa can be seen in 7.8a after a log transformation and the corresponding scores
plot is in Figure 7.8b. These figures show a clear separation of compounds according
to source with short chain alcohols to the right indicating marine materials and long
chain alcohols to the left indicating terrestrial plants. The branched chain compounds
show a range of associations indicating potential origins or different environments.
The locations in the scores plot (Figure 7.8b) also clearly separate according to their
chemical composition and indicate the marine influenced locations compared to the
terrestrial ones. Those sites adjacent to the sewage outfalls (e.g. 32-34) are located in
the area associated with branched compounds in Figure 7.8a.
Figure 7.8. The (a) loadings and (b) scores plots for fatty alcohols from the Ria Formosa lagoon after log transformation and Principal Components Analysis. (Data from Mudge, unpubl.)
Figure 7.9 The amount of variance in beach samples (the Y-Block) using the fatty alcohols measured in faecal matter from domesticated animals (cows etc.). CP = central pier, SP = south pier, NP = north pier. The pale blue bars are samples collected at the high water mark (HW), dark blue from the mid tide level (mid) and red from the low water (LW). Each bar is from a different week.
Given a suitable set of samples which characterise the fatty alcohols derived from
detergents, it would be possible to assess the contribution that this source made to any
environmental fatty alcohol profile. As a first attempt, the data used to generate
Figure 3.12 has been used to explain the profiles from the Ria Formosa lagoon in
Portugal. The predictable variance can be seen in Figure 7.10 for each of the sample
sites. The initial observation is that the values are considerably greater than might be
expected in reality – to expect that more than 10% of the compounds come from
detergents in such a system is not feasible. This highlights the inadequacy of using a
simple chemical profile approach. As the chemical used in the detergents are similar
to those found in nature, a degree of overlap is to be expected. A better approach may
be a constrained least squares approach such as that used by Burns et al. (1997).
Figure 7.10 The amount of variance in a dataset from the Ria Formosa predictable from the alcohol signature from a series of European STPs. The values are significantly greater than might be reasonably be expected.
Further investigation of the use of signatures needs to be made so as to accurately
predict the anthropogenic component in environmental samples. The best approaches
for this may be through the use of compound specific stable isotope analysis as there
is likely to be significant differences between the marine produced compounds and
those developed on land either as natural terrestrial materials or detergents.
References Abreu-Grobois, F. A., Billyard, T. C. and Walton, T. J. (1977). Biosynthesis of
heterocyst glycolipids of Anabaena cylindrica. Phytochemistry 16(3): 351-354.
Ackman, R. G., Tocher, C. S. and McLachlan, J. (1968). Marine phytoplankter fatty acids. J. Fish. Res. Board Can. 25: 1603-1620.
Albro, P. W. (1976). Bacterial waxes. Chemistry and Biochemistry of Natural Waxes. P. E. Kolattukudy. Amsterdam, Elsevier: 419-445.
Ali, H. A. M., Mayes, R. W., Hector, B. L. and Orskov, E. R. (2005). Assessment of n-alkanes, long-chain fatty alcohols and long-chain fatty acids as diet composition markers: The concentrations of these compounds in rangeland species from Sudan. Animal Feed Science and Technology 121(3-4): 257-271.
Avsejs, L. A. (2001). The Organic Geochemistry and Compound Specific Radiocarbon dating of Peat and other Sedimentary Materials. Ph.D. Thesis, Bristol University, pp211.
Avsejs, L. A., Nott, C. J., Xie, S. C., Maddy, D., Chambers, F. M. and Evershed, R. P. (2002). 5-n-Alkylresorcinols as biomarkers of sedges in an ombrotrophic peat section. Organic Geochemistry 33(7): 861-867.
Baker, E. W. and Louda, J. W. (1983). Thermal aspects in chlorophyll geochemistry. Advances in Organic Geochemistry. M. Bjorøy. Chichester, Wiley: 401–421.
Barreira, L. M., Bebianno, M. J., Mudge, S. M., Ferreira, A. M., Albino, C. I. and Veriato, L. M. (2005). Relationship between PCBs in suspended and settled sediments from a coastal lagoon. Ciencias Marinas 31(1B): 179-195.
Battersby, N. S., Sherren, A. J., Bumpus, R. N., Eagle, R. and Molade, I. K. (2001). The fate of linear alcohol ethoxylates during activated sludge treatment. Chemosphere 45: 109-121.
Bebianno, M. J. (1995). Effects of Pollutants in the Ria-Formosa-Lagoon, Portugal. Science of the Total Environment 171(1-3): 107-115.
Belanger, S. E. and Dorn, P. B. (2004). Chronic aquatic toxicity of alcohol ethoxylate (AE) surfactants under Canadian exposure conditions. 31st Annual Aquatic Toxicity Workshop, Charlottetown, Prince Edward Island, Canadian Technical Report of Fisheries and Aquatic Sciences.
Berg, J. M., Tymoczko, J. L. and Stryer, L. (2002). Biochemistry. New York, W.H. Freeman & Co.,
Berge, J.-P., Gouygou, J.-P., Dubacq, J.-P. and Durand, P. (1995). Reassessment of lipid composition of the diatom, Skeletonema costatum. Phytochemistry 39(5): 1017-1021.
Bishop, J. E. and Hajra, A. K. (1981). Mechanism and specificity of formation of long-chain alcohols by developing rat brain. J. Biol. Chem. 256: 9542–9550.
Boon, J. J., De Leeuw, J. W., V.d. Hoek, G. J. and Vosjan, J. H. (1977). Significance and taxonomic value of iso and anteiso monoenoic fatty acids and branched β-hydroxy acids in Desulphovibrio desulfuricans. J. Bacteriol. 129: 1183–1191.
Boon, J. J., Leeuw, J. W. d. and Burlingame, A. L. (1978). Organic geochemistry of Walvis Bay diatomaceous ooze--III. Structural analysis of the monoenoic and polycyclic fatty acids. Geochimica et Cosmochimica Acta 42(6, Part 1): 631-644.
Buckner, J. S., Mardaus, M. C. and Nelson, D. R. (1996). Cuticular lipid composition of Heliothis virescens and Helicoverpa zea pupae. Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology 114(2): 207-216.
Burkhard, L. P., Kuehl, D. W. and Veith, G. D. (1985). Evaluation of Reverse Phase Liquid-Chromatography Mass-Spectrometry for Estimation of N-Octanol Water Partition-Coefficients for Organic-Chemicals. Chemosphere 14(10): 1551-1560.
Burns, W. A., Mankiewicz, P. J., Bence, A. E., Page, D. S. and Parker, K. R. (1997). A principal-component and least-squares method for allocating polycyclic aromatic hydrocarbons in sediment to multiple sources. Environmental Toxicology and Chemistry 16(6): 1119-1131.
Caradec, S., Grossi, V., Gilbert, F., Guigue, C. and Goutx, M. (2004). Influence of various redox conditions on the degradation of microalgal triacylglycerols and fatty acids in marine sediments. Organic Geochemistry 35(3): 277-287.
Cheng, J. B. and Russell, D. W. (2004). Mammalian wax biosynthesis - I. Identification of two fatty acyl-coenzyme A reductases with different substrate specificities and tissue distributions. Journal of Biological Chemistry 279(36): 37789-37797.
Cheng, J. B. and Russell, D. W. (2004). Mammalian wax biosynthesis - II. ERxpression cloning of wax synthase cDNAs encoding a member of the acyltransferase enzyme family. Journal of Biological Chemistry 279(36): 37798-37807.
Chikaraishi, Y., Matsumoto, K., Ogawa, N. O., Suga, H., Kitazato, H. and Ohkouchi, N. (2005). Hydrogen, carbon and nitrogen isotopic fractionations during chlorophyll biosynthesis in C3 higher plants. Phytochemistry 66(8): 911-920.
Chikaraishi, Y. and Naraoka, H. (2005). δ13C and δD identification of sources of lipid biomarkers in sediments of Lake Haruna (Japan). Geochimica et Cosmochimica Acta 69(13): 3285-3297.
Cooper, L. L. D., Oliver, J. E., De Vilbiss, E. D. and Doss, R. P. (2000). Lipid composition of the extracellular matrix of Botrytis cinerea germlings. Phytochemistry 53(2): 293-298.
Dahl, K. A., Oppo, D. W., Eglinton, T. I., Hughen, K. A., Curry, W. B. and Sirocko, F. (2005). Terrigenous plant wax inputs to the Arabian Sea: Implications for the reconstruction of winds associated with the Indian Monsoon. Geochimica et Cosmochimica Acta 69(10): 2547-2558.
Dalton, C., Birks, H. J. B., Brooks, S. J., Cameron, N. G., Evershed, R. P., Peglar, S. M., Scott, J. A. and Thompson, R. (2005). A multi-proxy study of lake-development in response to catchment changes during the Holocene at Lochnagar, north-east Scotland. Palaeogeography Palaeoclimatology Palaeoecology 221(3-4): 175-201.
Daniel, J., Deb, C., Dubey, V. S., Sirakova, T. D., Abomoelak, B., Morbidoni, H. R. and Kolattukudy, P. E. (2004). Induction of a novel class of diacylglycerol acyltransferases and triacylglycerol accumulation in Mycobacterium tuberculosis as it goes into a dormancy-like state in culture. J. Bacteriol. 186: 5017–5030.
Doss, R. P. (1999). Composition and enzymatic activity of the extracellular matrix secreted by germlings of Botrytis cinerea. Applied and Environmental Microbiology 65(2): 404-408.
Dunphy, J. C., Pessler, D. G. and Morrall, S. W. (2001). Derivatization LC/MS for the simultaneous determination of fatty alcohol and alcohol ethoxylate surfactants
in water and wastewater samples. Environmental Science & Technology 35(6): 1223-1230.
Eadsforth, C. V., Sherren, A. J., Selby, M. A., Toy, R., Eckhoff, W. S., McAvoy, D. C. and Matthijs, E. (in press). Monitoring of environmental fingerprints of alcohol ethoxylates in Europe and Canada. Ecotoxicology and Environmental Safety.
Farías, L., Chuecas, L. A. and Salamanca, M. A. (1996). Effect of coastal upwelling on nitrogen regeneration from sediments and ammonium supply to the water column in Concepcíon Bay, Chile. Estuarine, Coastal and Shelf Science 43: 137-155.
Flory, J. E. and Hawley, G. R. W. (1994). A Hydrodictyon reticulatum Bloom at Loe Pool, Cornwall. European Journal of Phycology 29(1): 17-20.
Folch, J., Lees, M. and Stanley, G. H. S. (1957). A simple method for the isolation and purification of total lipides from animal tissues. J. Biol. Chem. 226(1): 497-509.
Gagosian, R. B. and Peltzer, E. T. (1986). The importance of atmospheric input of terrestrial organic matter to deep-sea sediments. Organic Geochemistry 10: 661-669.
Geladi, P. and Kowalski, B. R. (1986). Partial least squares regression: a tutorial. Anal. Chim. Acta 185: 1-17.
Haddad, R. I., Martens, C. S. and Farrington, J. W. (1992). Quantifying Early Diagenesis of Fatty-Acids in a Rapidly Accumulating Coastal Marine Sediment. Organic Geochemistry 19(1-3): 205-216.
Hamm, C. E. and Rousseau, V. (2003). Composition, assimilation and degradation of Phaeocystis globosa-derived fatty acids in the North Sea. Journal of Sea Research 50(4): 271-283.
Hansch, C., Quinlan, J. E. and Lawrence, G. L. (1968). Linear free-energy relationship between partition coefficients and the aqueous solubility of organic liquids. J. Org. Chem. 33(1): 347-350.
Hayeememon, A., Shameel, M., Ahmad, M., Ahmad, V. U. and Usmanghani, K. (1991). Phycochemical Studies on Gracilaria foliifera (Gigartinales, Rhodophyta). Botanica Marina 34(2): 107-111.
Hotham, A. (2001). Core profiles of biomarkers for land use change in salt and freshwater Scottish lochs. Undergraduate Project, University of Wales - Bangor, pp56.
Howell, V. J. (1984). Organic geochemistry of sediments from legs 67, 71 and 72 of the Deep Sea Drilling project. Ph.D. Thesis, University of Bristol, pp159.
Ishige, T., Tani, A., Sakai, Y. and Kato, N. (2003). Wax ester production by bacteria. Current Opinion in Microbiology 6(3): 244-250.
Itrich, N. R. and Federle, T. W. (2004). Effect of ethoxylate number and alkyl chain length on the pathway and kinetics of linear alcohol ethoxylate biodegradation in activated sludge. Environmental Toxicology and Chemistry 23(12): 2790-2798.
Jacob, J. (1976). Bird Waxes. Chemistry and Biochemistry of Natural Waxes. P. E. Kolattukudy. Amsterdam, Elsevier: 93-146.
Jeffrey, S. W. (1974). Profiles of photosynthetic pigments in the ocean using thin-layer chromatography. Marine Biology (Historical Archive) 26(2): 101-110.
Jeng, W. L. and Huh, C. A. (2004). Lipids in suspended matter and sediments from the East China Sea shelf. Organic Geochemistry 35(5): 647-660.
Jeng, W. L., Huh, C. A. and Chen, C. L. (1997). Alkanol and sterol degradation in a sediment core from the continental slope of southwestern Taiwan. Chemosphere 35(11): 2515-2523.
John, D. M., Douglas, G. E., Brooks, S. J., Jones, G. C., Ellaway, J. and Rundle, S. (1998). Blooms of the water net Hydrodictyon reticulatum (Chlorococcales, Chlorophyta) in a coastal lake in the British Isles: their cause, seasonality and impact. Biologia 53(4): 537-545.
Johns, R. B., Perry, G. J. and Jackson, K. S. (1977). Contribution of bacterial lipids to recent marine sediments. Estuarine and Coastal Marine Science 5(4): 521-529.
Ju, S. J. and Harvey, H. R. (2004). Lipids as markers of nutritional condition and diet in the Antarctic krill Euphausia superba and Euphausia crystallorophias during austral winter. Deep-Sea Research Part II-Topical Studies in Oceanography 51(17-19): 2199-2214.
Kalscheuer, R. and Steinbuchel, A. (2003). A novel bifunctional wax ester synthase/acyl-CoA : diacylglycerol acyltransferase mediates wax ester and triacylglycerol biosynthesis in Acinetobacter calcoaceticus ADP1. Journal of Biological Chemistry 278(10): 8075-8082.
Kaneda, T. (1967). Fatty acids of the genus Bacillus. Journal of Bacteriology 93: 894–903.
Kates, K. and Volcani, B. E. (1966). Lipid components of diatoms. Biochem. Biophys. Acta 116: 264-278.
Kates, M. (1964). Bacterial lipids. Advances in Lipid Research 2: 17–90. Kates, M. (1966). Biosynthesis of lipids in microorganisms. Annual Review of
Microbiology 20: 13-44. Kattner, G., Albers, C., Graeve, M. and Schnack-Schiel, S. B. (2003). Fatty acid and
alcohol composition of the small polar copepods, Oithona and Oncaea: indication on feeding modes. Polar Biology 26(10): 666-671.
Kattner, G., Gercken, G. and Eberlein, K. (1983). Development of lipids during a spring plankton bloom in the northern North Sea. I. Particulate fatty acids. Mar. Chem. 14: 149-162.
Kattner, G. and Graeve, M. (1991). Wax Ester Composition of the Dominant Calanoid Copepods of the Greenland Sea Fram Strait Region. Polar Research 10(2): 479-485.
Kattner, G. and Krause, M. (1989). Seasonal-Variations of Lipids (Wax Esters, Fatty-Acids and Alcohols) in Calanoid Copepods from the North-Sea. Marine Chemistry 26(3): 261-275.
Khan, A. A. and Kolattukudy, P. E. (1973). Microsomal Fatty-Acid Synthetase Coupled to Acyl-Coa Reductase in Euglena gracilis. Archives of Biochemistry and Biophysics 158(1): 411-420.
Kolattukudy, P. E. (1970). Reduction of Fatty Acids to Alcohols by Cell-Free Preparations of Euglena gracilis. Biochemistry 9(5): 1095-&.
Kolattukudy, P. E., Croteau, R. and Buckner, J. S. (1976). Biochemistry of Plant Waxes. Chemistry and Biochemistry of Natural Waxes. P. E. Kolattukudy. Amsterdam, Elsevier: 289-347.
Kolattukudy, P. E. and Rogers, L. (1978). Biosynthesis of Fatty Alcohols, Alkane-1,2-Diols and Wax Esters in Particulate Preparations from Uropygial Glands of White-Crowned Sparrows (Zonotrichia-Leucophrys). Archives of Biochemistry and Biophysics 191(1): 244-258.
Kolattukudy, P. E. and Rogers, L. (1986). Acyl-Coa Reductase and Acyl-Coa - Fatty Alcohol Acyl Transferase in the Microsomal Preparation from the Bovine Meibomian Gland. Journal of Lipid Research 27(4): 404-411.
Kravetz, L., Chung, H., Guin, K. F., Shebs, W. T. and Smith, L. S. (1984). Primary and ultimate biodegradation of an alcohol ethoxylate and nonylphenol ethoxylate under average winter conditions in the Unites States. Tenside Surfactants Detergents 21: 1-6.
Larsen, K. L., Miller, M. and Cox, R. P. (1995). Incorporation of Exogenons Long-Chain Alcohols into Bacteriochlorophyll-C Homologs by Chloroflexus-Aurantiacus. Archives of Microbiology 163(2): 119-123.
Lee, C., Wakeham, S. and Arnosti, C. (2004). Particulate organic matter in the sea: The composition conundrum. Ambio 33(8): 565-575.
Lehninger, A. L., Nelson, D. L. and Cox, M. M. (1993). Principles of Biochemistry. New York, Worth Publishers,
Leo, R. G. and Parker, P. L. (1966). Branched chain fatty acids in sediments. Science 152: 649–650.
Lepez, A. (1996). El emisario submarino como sistema de tratamiento de aguas servidas. (Subtidal emission with a treatment system for service waters), ESSBIO S.A.: 19.
Madureira, L. A. D. S. (1994). Lipids in Recent Sediments of the Eastern North Atlantic. Ph.D. Thesis, Bristol University, pp246.
McEvoy, J. (1983). The Origin and Diagenesis of Organic Lipids in Sediments from the San Miguel Gap. Ph.D. Thesis, Bristol University, pp507.
Metz, J. G., Pollard, M. R., Anderson, L., Hayes, T. R. and Lassner, M. W. (2000). Purification of a jojoba embryo fatty acyl-coenzyme A reductase and expression of its cDNA in high erucic acid rapeseed. Plant Physiology 122(3): 635-644.
Modler, R. F. (2004). Detergent Alcoholos. CEH Marketing Research Report, SRI Consulting: 16.
Mohd. Ali, M. (2003). Multivariate Statistical Analyses in Lipid Biomarker Studies. Ph.D. Thesis, University of Wales, Bangor, pp277.
Morrall, S. W., Dunphy, J. C., Cano, M. L., Evans, A., McAvoy, D. C., Price, B. P. and Eckhoff, W. S. (in press). Removal and environmental exposure of alcohol ethoxylates in US sewage treatment. Ecotoxicology and Environmental Safety.
Mudge, S. M. (2001). The Source of Organic Matter on Blackpool Beaches (2000), University of Wales, Bangor.
Mudge, S. M. (2002). Reassessment of the hydrocarbons in Prince William Sound and the Gulf of Alaska: Identifying the source using partial least- squares. Environmental Science & Technology 36(11): 2354-2360.
Mudge, S. M., Bebianno, M., East, J. A. and Barreira, L. A. (1999). Sterols in the Ria Formosa lagoon, Portugal. Water Research 33(4): 1038-1048.
Mudge, S. M., Birch, G. F. and Matthai, C. (2003). The effect of grain size and element concentration in identifying contaminant sources. Environmental Forensics 4(4): 305-312.
Mudge, S. M. and Duce, C. (2005). Identifying the Source, Transport Path and Sinks of Sewage Derived Organic Matter. Environmental Pollution.
Mudge, S. M. and Duce, C. E. (2005). Identifying the source, transport path and sinks of sewage derived organic matter. Environmental Pollution 136(2): 209-220.
Mudge, S. M., East, J. A., Bebianno, M. J. and Barreira, L. A. (1998). Fatty acids in the Ria Formosa Lagoon, Portugal. Organic Geochemistry 29(4): 963-977.
Mudge, S. M., Hooper, L. and Icely, J. D. (1998). Biomarkers associated with sewage in the Arade Estuary, Portugal. Environmental Technology 19(10): 1055-1059.
Mudge, S. M. and Lintern, D. G. (1999). Comparison of sterol biomarkers for sewage with other measures in Victoria Harbour, BC, Canada. Estuarine Coastal and Shelf Science 48(1): 27-38.
Mudge, S. M. and Norris, C. E. (1997). Lipid biomarkers in the Conwy Estuary (North Wales, UK): A comparison between fatty alcohols and sterols. Marine Chemistry 57(1-2): 61-84.
Mudge, S. M. and Norris, G. E. (1997). Lipid biomarkers in the Conwy Estuary (North Wales, UK): A comparison between fatty alcohols and sterols. Marine Chemistry 57(1-2): 61-84.
Mudge, S. M. and Seguel, C. G. (1997). Trace organic contaminants and lipid biomarkers in Concepcion and San Vicente Bays. Boletin De La Sociedad Chilena De Quimica 42(1): 5-15.
Mudge, S. M. and Seguel, C. G. (1999). Organic contamination of San Vicente Bay, Chile. Marine Pollution Bulletin 38(11): 1011-1021.
Nash, D., Leeming, R., Clemow, L., Hannah, M., Halliwell, D. and Allen, D. (2005). Quantitative determination of sterols and other alcohols in overland flow from grazing land and possible source materials. Water Research 39(13): 2964-2978.
Nelson, D. R., Fatland, C. L., Buckner, J. S. and Freeman, T. P. (1999). External lipids of adults of the giant whitefly, Aleurodicus dugesii. Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology 123(2): 137-145.
Newton, A. and Mudge, S. M. (2005). Lagoon-sea exchanges, nutrient dynamics and water quality management of the Ria Formosa (Portugal). Estuarine, Coastal and Shelf Science 62(3): 405-414.
Nott, C. J. (2000). Biomarkers in Ombrotrophic Mires as Palaeoclimate Indicators. Ph.D. Thesis, Bristol University, pp231.
Nott, C. J., Xie, S. C., Avsejs, L. A., Maddy, D., Chambers, F. M. and Evershed, R. P. (2000). n-Alkane distributions in ombrotrophic mires as indicators of vegetation change related to climatic variation. Organic Geochemistry 31(2-3): 231-235.
O'Leary, W. M. (1962). The fatty acids of bacteria. Bacteriological Reviews 26: 421–447.
Otto, A., Shunthirasingham, C. and Simpson, M. J. (2005). A comparison of plant and microbial biomarkers in grassland soils from the Prairie Ecozone of Canada. Organic Geochemistry 36(3): 425-448.
Parkes, R. J. and Taylor, J. (1983). The relationship between fatty acid distributions and bacterial respiratory types in contemporary marine sediments. Estuarine, Coastal and Shelf Science 16(2): 173-174.
Perry, G. J., Volkman, J. K., Johns, R. B. and Bavor, J., H. J. (1979). Fatty acids of bacterial origin in contemporary marine sediments. Geochimica et Cosmochimica Acta 43(11): 1715-1725.
Perry, J. J., Staley, J. T. and Lory, S. (2002). Microbial Life. Sunderland, Massachusetts, Sinauer Associates,
Pickering, D. A. (1987). Chemical and Physical Analysis of Laminated Sediment formed in Loe Pool, Cornwall. Ph.D. Thesis, Plymouth Polytechnic, pp376.
Prahl, F. G., Muelhausen, L. A. and Lyle, M. (1989). An organic geochemical assessment of oceanographic conditions at MANOP Site C over the past 26,000 years. Paleoceanography 4: 495-510.
Reiser, S. and Somerville, C. (1997). Isolation of mutants of Acinetobacter calcoaceticus deficient in wax ester synthesis and complementation of one mutation with a gene encoding a fatty acyl coenzyme A reductase. J. Bacteriol. 179: 2969–2975.
Rezanka, T. and Podojil, M. (1986). Identification of wax esters of the fresh-water green alga Chlorella kessleri by gas chromatography-mass spectrometry. Journal of Chromatography A 362: 399-406.
Rezanka, T., Vyhnalek, O. and Podojil, M. (1986). Identification of sterols and alcohols produced by green algae of the genera Chlorella and Scenedesmus by means of gas chromatography-mass spectrometry. Folia Microbiology 31: 44–49.
Rock, C. O. and Cronan, J. E. (1996). Escherichia coli as a model for the regulation of dissociable (type II) fatty acid biosynthesis. Biochimica Et Biophysica Acta-Lipids and Lipid Metabolism 1302(1): 1-16.
Roper, M. M. (2004). The isolation and characterisation of bacteria with the potential to degrade waxes that cause water repellency in sandy soils. Australian Journal of Soil Research 42(4): 427-434.
Sargent, J. R. and Falk-Petersen, S. (1988). The Lipid Biochemistry of Calanoid Copepods. Hydrobiologia 167: 101-114.
Sargent, J. R., Lee, R. F. and Nevenzel, J. C. (1976). Marine Waxes. Chemistry and Biochemistry of Natural Waxes. P. E. Kolattukudy. Amsterdam, Elsevier: 49-91.
Scott, J. A. (2004). Mountain lake sedimentary biomarker records as indicators of holocene climate variability. Ph.D. Thesis, University of Bristol, pp218.
Seguel, C. G., Mudge, S. M., Salgado, C. and Toledo, M. (2001). Tracing sewage in the marine environment: Altered signatures in Conception Bay, Chile. Water Research 35(17): 4166-4174.
Shuman, F. R. and Lorenzen, C. J. (1975). Quantitative degradation of chlorophyll by a marine herbivore. Limnol. Oceanogr. 20: 580–586.
Soltani, M., Metzger, P. and Largeau, C. (2004). Effects of hydrocarbon structure on fatty acid, fatty alcohol, and beta-hydroxy acid composition in the hydrocarbon-degrading bacterium Marinobacter hydrocarbonoclasticus. Lipids 39(5): 491-505.
Steber, J. and Wierich, P. (1983). The environmental fate of detergent range fatty alcohol ethoxylates - biodegradation studies with a 14C labeled model surfactant. Tenside Surfactants Detergents 20: 183-187.
Sun, M. Y. and Wakeham, S. G. (1994). Molecular Evidence for Degradation and Preservation of Organic Matter in the Anoxic Black-Sea Basin. Geochimica Et Cosmochimica Acta 58(16): 3395-3406.
Sun, M. Y., Wakeham, S. G. and Lee, C. (1997). Rates and mechanisms of fatty acid degradation in oxic and anoxic coastal marine sediments of Long Island Sound, New York, USA. Geochimica et Cosmochimica Acta 61: 341-355.
Tewari, Y. B., Miller, M. M., Wasik, S. P. and Martire, D. E. (1982). Aqueous Solubility and Octanol Water Partition-Coefficient of Organic-Compounds at 25.0-Degrees-C. Journal of Chemical and Engineering Data 27(4): 451-454.
Tornabene, T. G., Gelpi, E. and Oro, J. (1967). Identification of the fatty acids and aliphatic hydrocarbons in Sarcina lutea by gas chromatography and combined gas chromatography-mass spectrometry. Journal of Bacteriology 94: 333–343.
Tulloch, A. P. (1976). Chemistry of Waxes of Higher Plants. Chemistry and Biochemistry of Natural Waxes. P. E. Kolattukudy. Amsterdam, Elsevier: 235-287.
Unsworth, R. K. F. (2001). Sedimentary lipid and PAH biomarkers as temporal indicators of change within the western area of the Ria Formosa Lagoon, Portugal. M.Sc. Thesis, University of Wales, Bangor, pp88.
van Compernolle, R., McAvoy, D., Sherren, A., Wind, T., Cano, M. L., Belanger, S. E., Dorn, P. B. and Kerr, K. M. (in press). Predicting the Sorption of Fatty Alcohols and Alcohol Ethoxylates to Effluent and Receiving Water Solids. Ecotoxicology and Environmental Safety.
Vioque, J. and Kolattukudy, P. E. (1997). Resolution and purification of an aldehyde-generating and an alcohol-generating fatty acyl-CoA reductase from pea leaves (Pisum sativum L). Archives of Biochemistry and Biophysics 340(1): 64-72.
Volkman, J. K., Barrett, S. M., Blackburn, S. I., Mansour, M. P., Sikes, E. L. and Gelin, F. (1998). Microalgal biomarkers: A review of recent research developments. Organic Geochemistry 29(5-7): 1163-1179.
Volkman, J. K., Barrett, S. M., Dunstan, G. A. and Jeffrey, S. W. (1992). C30---C32 alkyl diols and unsaturated alcohols in microalgae of the class Eustigmatophyceae. Organic Geochemistry 18(1): 131-138.
Volkman, J. K., Gatten, R. R. and Sargent, J. R. (1980). Composition and Origin of Milky Water in the North-Sea. Journal of the Marine Biological Association of the United Kingdom 60(3): 759-768.
Wakeham, S. G., Lee, C., Hedges, J. I., Hernes, P. J. and Peterson, M. L. (1997). Molecular indicators of diagenetic status in marine organic matter. Geochimica et Cosmochimica Acta 61(24): 5363-5369.
Waltermann, M., Hinz, A., Robenek, H., Troyer, D., Reichelt, R., Malkus, U., Galla, H. J., Kalscheuer, R., Stoveken, T., von Landenberg, P. and Steinbuchel, A. (2005). Mechanism of lipid-body formation in prokaryotes: how bacteria fatten up. Molecular Microbiology 55(3): 750-763.
Wang, X. and Kolattukudy, P. E. (1995). Solubilization and Purification of Aldehyde-Generating Fatty Acyl-CoA Reductase from Green Alga Botryococcus braunii. Febs Letters 370(1-2): 15-18.
Wind, T., Stephenson, R. J., Eadsforth, C. V., Sherren, A. and Toy, R. (in press). Determination of the fate of alcohol ethoxylate homologues in a laboratory continuous activated-sludge unit study. Ecotoxicology and Environmental Safety.
Wold, S., Albano, C., Dunn, W. J., Edlund, U., Esbensen, K., Geladi, P., Hellberg, S., Johansson, E., Lindberg, W. and Sjöström, M. (1984). Multivariate data analysis in chemistry. Chemometrics: Mathematics and Statistics in Chemistry. B. R. Kowalski. Dordrecht, Holland, D. Reidel Publishing Company.
Wu, X.-Y., Moreau, R. A. and Stumpf, P. K. (1981). Studies of biosynthesis of waxes by developing jojoba seed. III. Biosynthesis of wax esters from acyl-CoA and long-chain alcohols. Lipids 6: 897–902.
Xie, S. C., Nott, C. J., Avsejs, L. A., Maddy, D., Chambers, F. M. and Evershed, R. P. (2004). Molecular and isotopic stratigraphy in an ombrotrophic mire for
paleoclimate reconstruction. Geochimica et Cosmochimica Acta 68(13): 2849-2862.
Yunker, M. B., Macdonald, R. W., Veltkamp, D. J. and Cretney, W. J. (1995). Terrestrial and Marine Biomarkers in a Seasonally Ice-Covered Arctic Estuary - Integration of Multivariate and Biomarker Approaches. Marine Chemistry 49(1): 1-50.
Zhang, Y. M., Lu, Y. J. and Rock, C. O. (2004). The reductase steps of the type II fatty acid synthase as antimicrobial targets. Lipids 39(11): 1055-1060.
Appendix 1. DETERGENT ALCOHOLS – A SUMMARY OF FEEDSTOCKS, PROCESSES AND END PRODUCTS By Allen M. Nielsen
Detergent range alcohols are defined as alcohols containing twelve or more carbons (commonly restricted to the C12-C18 range) and used mainly in detergent applications. These alcohols are commercially produced in a number of ways, but the resulting products are usually classified according to the source of raw materials used to produce them. There are two general categories: those derived from fats and oils (oleochemical) and those derived from crude oil, natural gas, natural gas liquids or coal (petrochemical). OLEOCHEMCIAL BASED ALCOHOLS In natural fats and oils the hydrocarbon chains have already been formed in the raw material. Biological processes in living organisms synthesize long carbon chains in the form of triglycerides. From plant and animal oils the triglycerides are separated and chemically converted into key alcohol intermediates. Coconut oil and palm kernel oil are preferred for the production of C12-C14 chain lengths. Animal fats (tallow) and palm oil are preferred for the production of C16-C18 chain lengths (Table A1). Table A1. Composition of Natural Triglycerides (wt %)
Trig
lyce
ride
Fat
or O
il
Cap
rylic
Cap
ric
Laur
ic
Myr
istic
Myr
isto
leic
Pent
adec
anoi
c
Palm
itic
Palm
itole
ic
Mar
garic
Stea
ric
Ole
ic
Lino
leic
Lino
leni
c
C8 C10 C12 C14 C14 C15 C16 C16 C17 C18 C18 C18
C18
Tallow
3.2 1.0 0.4 26.4 2.6 0.9 26.9 36.7 (1)
Palm
0.9 46.6 4.1 39.3 9.1
Coconut
8.0 6.7 51.3 16.2 7.6 2.7 5.9 1.6
Palm Kernel
4.0 5.0 50.0 15.0 7.0 0.5 2.0 15.0 1.0
Fatty Acids In general, the ester linkage in the triglyceride molecules can be severed in two ways. In one process steam is used to hydrolyze the triglycerides to yield fatty acids and glycerin. (Figure A1)
Triglyceride Glycerin Fatty Acids Figure A1. Fatty Acid Production (Fat Splitting) Fatty Methyl Esters In the other process methanol is used to transesterify the triglycerides to yield fatty methyl esters and glycerin. (Figure A2)
R1 C OCH2
O
OCHCR2
O
OCH + 3CH2OH
OCH2CR3
O
HOCH +
HOCH2
HOCH2
R2 C OCH3
OR1 C OCH3
O
R3 C OCH3
O
Triglyceride Glycerin
Methanol
Methyl Esters Figure A2. Methyl Ester Production Oleo Chemical Fatty Alcohols Oleo chemical fatty alcohols of the C12 to C18 chain lengths are produced by the hydrogenation of both fatty methyl esters and fatty acids (Figures A3 and A4).
Figure A4. Summary of Oleo Chemical Alcohol Production These alcohols are even carbon chain lengths, >99% linear, primary alcohols. Fatty alcohols are important oleochemcial-based surfactant intermediates. From them are made many surfactant products including alcohol sulphates, alcohol ethoxylates and alcohol ether sulphates PETROCHEMCIAL BASED ALCOHOLS Alcohols based on Petroleum Linear hydrocarbon chains or normal paraffin can be extracted from petroleum fractions. Kerosene and gas oil are different boiling fractions of petroleum that contain hydrocarbons of the C10-C16 and higher chain lengths.
Normal Paraffin Kerosene is an important hydrocarbon source. Using molecular sieve separation process such as MOLEX OR ISOSIV, the linear or normal paraffin are separated from the branched and cyclic hydrocarbons. The normal paraffin is distilled into various cuts and the branched/cyclic hydrocarbon stream or raffinate is sold as an upgraded fuel (Figure A5). Figure A5. Normal Paraffin Production Internal Olefins Pure Internal olefins can be produced from normal linear paraffin. In the combined PACOL/OLEX process, dilute PACOL olefins are concentrated by the OLEX process to about 96% internal olefins (Figures A6 and A7).
Conventional OXO Alcohols Based on Internal Olefins Internal olefins can be converted to conventional OXO alcohols. In contrast to oleo chemical based alcohols, OXO alcohols have both odd and even carbon chain lengths and they have up to 50% branching at the second carbon position. OXO (Hydroformylation Reaction) The OXO reaction as applied to the synthesis of detergent-range alcohols involves the reaction of olefins with synthesis gas (CO/H2) in the presence of an OXO catalyst to yield higher alcohols. The sequence of steps includes: hydroformylation, catalyst removal and recycle, aldehyde distillation, aldehyde hydrogenation and purification of the product alcohols as shown in Figure A8.
1. R1CH CHR2 + CO/H2catalyst R3C O + R4
H
C C
R5
H
O
H
alpha- or internalolefin
synthesisgas
linearaldehyde
branchedaldehyde
2. R3C
H
O + R4 C
R5
H
C
H
O catalystH2 R3 CH2OH + R4 C
R5
CH2OH
H
aldehyde mixture linear alcohol branched alcohol Figure A8. OXO Process Alcohols based on Ethylene Ziegler Ethylene Growth Process Ethylene is used as a building block to form long hydrocarbon chains. This process employs what is called a growth reaction to make hydrocarbon chains from C2 to C20 in length. Hydrocarbon chains are grown by adding ethylene units to an organometallic compound such as triethyl aluminium. The ethylene units are inserted between the growing alkyl chains and the aluminium, producing trialkyl aluminium or growth product as noted in Figure A9.
Trialkyl Aluminum Figure A9. Ziegler Ethylene Growth Process Ziegler Alcohols Further processing of the growth product yields linear primary alcohols. In the Ziegler alcohol process linear, even-carbon-chain fatty alcohols are produced from the growth product by controlled oxidation followed by hydrolysis. For a given chain length, these alcohols are essentially identical to natural alcohols, having linear, even-carbon-chain length primary structures. A stoichiometric amount of aluminium is used in this process that eventually is converted into high-purity alumina after hydrolysis (Figures A10 and A11).
Figure A11. Ziegler Alcohol Process Modified OXO Alcohols SHOP Alpha Olefins The SHOP process employs an ethylene oligomerization reaction to make alpha olefins. In the first part of the process linear, even-carbon-chain alpha olefins are produced. As with other ethylene growth reactions, the olefins are produced in a broad distribution of carbon chain lengths. Some of these chain lengths are more desirable as alpha olefin products than others and are separated by distillation and sold. SHOP Internal Olefins and Modified OXO Alcohols In the second part of the SHOP process, alpha olefins of the less desirable chain lengths are converted to linear internal olefins in a complicated process called isomerization/disproportionation/metathesis. The internal olefins produced in this process have both odd and even chain lengths in the range of C10 to C14 as summarized in Figure A12.
Figure A12. SHOP Olefin Process Internal olefins from the SHOP process are converted in the Modified OXO process which produces alcohols having 20% branching. (Figure A13)
Shell’s commercial mono-methyl branched alcohol is in the C16 – C17 range. The starting material in the upper left hand side of Figure A14 is a linear internal olefin (IO). The top reaction shows the route to traditional NEODOL® Alcohols from an IO. The lower reactions show how Shell converts a linear internal olefin into a branched IO. Standard modified-OXO chemistry converts the branched IO into a branched primary alcohol. Each of these structures depicts one of many possible isomers. The commercial product is >95 % branched, but fully biodegradable.
OH
OH
CatalystNEODOL 45
Mono-methylbranched alcohol
Mono-methylbranched internal olefin
ModifiedOXO
ModifiedOXO
Figure A14. Modified OXO process for mid-range alcohols. OXO Alcohols Derived from Fischer-Tropsch Alpha Olefins The process begins with the production of synthesis (syngas) from either coal or natural gas. Syngas is then converted to a liquid hydrocarbon stream in the Fischer-Tropsch (F-T) process (Figure A15). Figure A15. Fischer-Tropsch Process This stream consists of both even and odd chain-length hydrocarbons in a Shultz-Flory distribution, the principal components are alpha olefins. The C11, C12 hydrocarbons are separated by distillation. Hydroformylation, using CO and H2, then serves to select the olefinic portion of that stream to make long-chain aldehydes. Further hydrogenation and purification yield the F-T oxo 1213 alcohol. F-T alcohols are 50% branched, but randomly branched because of methyl-branching in the precursor olefins. The process flow is summarized in Figure A16.
Figure A16. Fischer-Tropsch OXO Alcohol Process SUMMARY A comparison of the major detergent alcohols is shown below in Table A2. Table A2. Comparison of Detergent Alcohols Alcohol Type Raw Material Carbon Chain Distribution Percent Linear
Oleo chemical coconut oil, PKO C10 - C18 even only 100%
Ziegler ethylene C2 - C20 even only 98%
Modified OXO ethylene C12 - C15 even and odd 80%
Regular OXO n-paraffin C12 - C15 even and odd 50%
REFERENCES
1. Matheson, K. Lee. 1996. Surfactants Raw Materials: Classification, Synthesis, and Uses. In Soaps and Detergents: A Theoretical and Practical Review. Ed. Luis Spitz. AOCS Press, Champaign, Illinois, pp. 288-303.
2. Grant-Huyser, M., S. Maharaj, L. Matheson, L. Rowe, and E. Sones. 2004.
Ethoxylation of Detergent-Range OXO Alcohols Derived from Fischer-Tropsch α-Olefins. J. Surfactants and Detergents: 7(4) pp. 397-407.
3. Modler, R.F., R. Gubler and Y. Inoguchi. 2004. Detergent Alcohols. CEH
Marketing Research Report. CEH-SRI International. pp. 1-71.